And you are complaining that the print messages appear in the console but the label doesn't change until much later.

This sort of delay is nearly always caused by a threading issue. You do not show MyFunction and you do not show the entirety of closure, so it's impossible to help you in detail, but the likelihood is that you are messing around with background threads without knowing what you are doing, and that you have accidentally set myLabel.text on a background thread, which is a big no-no. You must step out to the main thread in order to touch the interface in any way: